This application is a divisional of U.S. application Ser. No. 13/899,452, filed May 21, 2013, now U.S. Pat. No. 8,872,000, which application is a divisional of U.S. application Ser. No. 13/213,021, filed Aug. 18, 2011, now U.S. Pat. No. 8,466,345, which application is a divisional of U.S. application Ser. No. 12/045,562, filed Mar. 10, 2008, now U.S. Pat. No. 8,030,544, which application claims the priority of U.S. Provisional application Ser. Nos. 60/894,096, filed Mar. 9, 2007, and 60/915,066, filed Apr. 30, 2007, the entire disclosures of all of which are incorporated herein by reference in their entirety.
1. Field of the Invention
The invention relates generally to methods for preparing and transforming meristematic plant tissue and selection and subsequent regeneration of transgenic plants.
2. Description of Related Art
Transformed plants may be obtained by directly treating meristematic tissue of a plant embryo. The meristematic tissue contains formative plant cells that differentiate to produce multiple plant structures including stem, roots, leaves, germ line tissue, and seeds. The meristematic tissue, such as soybean tissue, may be excised from seeds. Methods of genetically transforming soybeans (Glycine max) using bacterially-mediated gene transfer directly on the meristematic cells of soybean embryos are known. Isolated cotton meristems and shoot apex tissues have been transformed. Use of a cytokinin to induce shoot development in tissue culture has been reported.
A number of selective agents are known for use in methods for genetically transforming plant cells. An aminoglycoside-3′-adenyltransferase has been used as a selectable marker in transforming plant cells. Fusion of aadA with a chloroplast transit peptide-encoding sequence, to allow for directing a nuclear produced AadA to the chloroplast, has not been reported.